Which compound has the LEAST percent composition by mass of sulfur?

What mass of radon is in 8.17 moles of radon?

Len [333]

Answer:

1813.74g

Explanation:

Given parameters:

Number of moles of radon = 8.17moles

Unknown:

Mass of radon = ?

Solution:

To solve this problem, we use the expression below:

Number of moles = $\frac{mass}{molar mass}$

Molar mass of radon = 222g/mol

Now insert the parameters and solve;

Mass of radon = Number of moles x molar mass

= 8.17 x 222

= 1813.74g

4 0

3 years ago

4. An 82 kg hiker climbs Mt. Humphrey near Flagstaff. During a two hour period, the hiker's

bazaltina [42]

Answer:

$\Delta E = 434253.96\,J$ , $\Delta P = 60.313\,W$

Explanation:

The change in energy is given by the change in gravitational potential energy:

$\Delta E = m\cdot g \cdot \Delta h$

$\Delta E = (82\,kg)\cdot (9.807\,\frac{m}{s^{2}} )\cdot (540\,m)$

$\Delta E = 434253.96\,J$

The average rate of change in terms of time is approximately this:

$\Delta P = \frac{\Delta E}{\Delta t}$

$\Delta P = \frac{434253.96\,J}{(2\,h)\cdot (\frac{3600\,s}{1\,h} )}$

$\Delta P = 60.313\,W$

8 0

3 years ago

In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. Which postulate of ki

Levart [38]

Answer:

Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy.

Explanation:

When a gas is paced in a container, the molecules of the gas have little or no intermolecular interaction between them. There is a lot of space between the molecules of the gas.

The gas molecules move at very high speed and collide with each other and with the walls of container.

The collision of these particles with each other is perfectly elastic hence the kinetic energy of the colliding gas particles do not change.

7 0

3 years ago

7.00 of Compound x with molecular formula C3H4 are burned in a constant-pressure calorimeter containing 35.00kg of water at 25c.

beks73 [17]

Answer:

$\Delta H_{f,C_3H_4}=276.8kJ/mol$

Explanation:

Hello!

In this case, since the equation we use to model the heat exchange into the calorimeter and compute the heat of reaction is:

$\Delta H_{rxn} =- m_wC_w\Delta T$

We plug in the mass of water, temperature change and specific heat to obtain:

$\Delta H_{rxn} =- (35000g)(4.184\frac{J}{g\°C} )(2.316\°C)\\\\\Delta H_{rxn}=-339.16kJ$

Now, this enthalpy of reaction corresponds to the combustion of propyne:

$C_3H_4+4O_2\rightarrow 3CO_2+2H_2O$

Whose enthalpy change involves the enthalpies of formation of propyne, carbon dioxide and water, considering that of propyne is the target:

$\Delta H_{rxn}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{f,C_3H_4}$

However, the enthalpy of reaction should be expressed in kJ per moles of C3H4, so we divide by the appropriate moles in 7.00 g of this compound:

$\Delta H_{rxn} =-339.16kJ*\frac{1}{7.00g}*\frac{40.06g}{1mol}=-1940.9kJ/mol$

Now, we solve for the enthalpy of formation of C3H4 as shown below:

$\Delta H_{f,C_3H_4}=3\Delta H_{f,CO_2}+2\Delta H_{f,H_2O}-\Delta H_{rxn}$

So we plug in to obtain (enthalpies of formation of CO2 and H2O are found on NIST data base):

$\Delta H_{f,C_3H_4}=3(-393.5kJ/mol)+2(-241.8kJ/mol)-(-1940.9kJ/mol)\\\\\Delta H_{f,C_3H_4}=276.8kJ/mol$

Best regards!

7 0

3 years ago

What’s IV DV and Controls

zavuch27 [327]

Answer:

Iv-Independent Variable the part that doesnt get affected by the Dependent. DV- Dependent Variable- the part that gets affected by the independent. Controls is what everything is gettong compared to

7 0

3 years ago